Method and device for detecting performance loss of underwater concrete mixture

The invention provides an underwater concrete mixture performance loss detection method and device, and the method comprises the steps: uniformly mixing concrete, and dividing the concrete into two equal parts; detecting the slump, the expansion degree, the volume weight, the 7-day compressive strength and the 28-day compressive strength of one part of concrete mixture; an outer barrel with the closed bottom is taken, a proper amount of water is added, an inner barrel with holes distributed in the side wall is put into the outer barrel, another sample is injected into the inner barrel through a guide pipe method, meanwhile, water circulation in the outer barrel is kept, and the water level is higher than the concrete surface till concrete pouring is completed; taking out the concrete in the barrel for test detection; uniformly mixing the concrete in the barrel, detecting the slump, the expansion degree and the volume weight of the concrete, and forming 7-day strength and 28-day strength of the concrete; and a